Integrated Capacitor Filter and Integrated Capacitor Filter with Varistor Function

ABSTRACT

Disclosed are apparatus and a method for providing an integrated multiterminal multilayer ceramic device that has three or more capacitive elements. Two of such capacitive elements may be in series, with a third in parallel. The integrated device may be packaged as an overmolded three leaded component, or can be mounted as SMD (surface mount device). The integrated device may also be combined with a separate varistor in a stacked arrangement of leaded components.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims filing benefit of U.S. Provisional PatentApplication Ser. No. 62/455,076 having a filing date of Feb. 6, 2017,and which is incorporated herein by reference in its entirety.

BACKGROUND OF THE SUBJECT MATTER

For some time, the design of various electronic components has beendriven by a general industry trend toward miniaturization, as well asincreased functionality. In such regard, a need exists for ever smallerelectronic components having improved operating characteristics. Forexample, some applications would benefit from the equivalent of multiplecomponents, but are severely limited in the amount of space suchelectronic components may occupy on a circuit board.

Multilayer ceramic devices, such as multilayer ceramic capacitors orvaristors, are sometimes constructed with a plurality ofdielectric-electrode layers arranged in a stack. During manufacture, thelayers may be pressed and formed into a vertically stacked structure.Multilayer ceramic devices can include a single element or multipleelements. Examples of prior issued U.S. Patents or U.S. PatentApplication Publications include: U.S. Pat. Nos. 9,025,306; 7,307,829;and 5,870,273; and U.S. Patent Application Publication Nos. 20120188681;20090154055; 20090147440; and 20060262490, all of which are herebyincorporated by reference into this disclosure for all purposes, and asif fully set forth herein.

It would be advantageous, therefore, if devices and corresponding methodcould be provided that result in improved miniaturization, as well asincreased functionality and/or operational characteristics.

SUMMARY OF THE SUBJECT MATTER

In accordance with one embodiment of the present invention, amultiterminal multilayer ceramic device with multiple capacitiveelements is disclosed. The multiterminal multilayer ceramic devicecomprises: a body having cooperating multiple layers including electrodelayers to form integrated capacitive structures; a first region of saidelectrode layers forming a split feedthrough type construction of tworespective capacitors; a second region of said electrode layers formingan overlap type construction of a multilayer ceramic capacitor; a firstpair of terminations external to said body and having opposite polarity;and a second pair of terminations external to said body and having thesame polarity; wherein said first pair of terminations is in seriesconnection with said second region capacitor, and said first pair ofterminations and at least one of said second pair of terminations are inrespective parallel connections with said two respective capacitors ofsaid first region, so that multiple capacitive elements are integratedin a single package device.

In accordance with another embodiment of the present invention, anintegrated capacitor filter with varistor functionality is disclosed.The Integrated capacitor filter comprises: a discrete multiterminalmultilayer ceramic capacitor device with multiple capacitive elements,comprising a body having cooperating multiple layers including electrodelayers which in turn form integrated capacitive structures; a first pairof capacitor device terminations external to said body and havingopposite polarity; a second pair of capacitor device terminationsexternal to said body and having the same polarity; a first region ofsaid electrode layers forming two respective capacitors; and a secondregion of said electrode layers forming a multilayer ceramic capacitorreceived in series connection between said first pair of terminations; adiscrete varistor comprising a body having a pair of varistorterminations external to said varistor body and having oppositepolarity; first and second leads respectively attached to said firstpair of capacitor device terminations and said pair of varistorterminations; and a third lead attached to at least one of said secondpair of capacitor device terminations.

In accordance with another embodiment of the present invention, a methodfor providing a multiterminal multilayer ceramic device with multiplecapacitive elements is disclosed. The method comprises the followingsteps: providing a body having cooperating multiple layers includingelectrode layers which are used to form integrated capacitivestructures; forming a split feedthrough type construction of tworespective capacitors in a designated first region of said electrodelayers; forming an overlap type construction of a multilayer ceramiccapacitor in a designated second region of said electrode layers;applying a first pair of terminations external to a pair of respectiveopposing sides of said body, and with said second region capacitorconnected in series between said first pair of terminations; andapplying a second pair of terminations external to at least portions ofanother pair of respective opposing sides of said body and having thesame polarity, and with at least one of said second pair of terminationsand said first pair of terminations in respective parallel connectionswith said two respective capacitors of said first region, so thatmultiple capacitive elements are integrated in a single package device.

Other features and aspects of the present invention are discussed ingreater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the presently disclosed subjectmatter, including the best mode thereof, directed to one of ordinaryskill in the art, is set forth in the specification, which makesreference to the appended figures, in which:

FIG. 1A illustrates an external perspective view of an exemplaryembodiment of a multiterminal multilayer device in accordance withpresently disclosed subject matter, for use such as for an SMDconfiguration;

FIG. 1B illustrates a perspective view of the exemplary embodiment ofapplication FIG. 1A, with partial transparent view to illustratemultiple components formed by multilayer construction therein;

FIG. 1C illustrates a perspective view of the exemplary embodiment ofapplication FIG. 1A, with added lead configuration;

FIG. 1D illustrates a schematic view of the exemplary embodiment ofapplication FIG. 1A;

FIG. 2 illustrates a perspective view of another exemplary embodiment ofpresently disclosed subject matter, with partial transparent view toillustrate multiple components formed by multilayer constructiontherein;

FIG. 3A illustrates an external perspective view of another exemplaryembodiment of a multiterminal multilayer device in accordance withpresently disclosed subject matter;

FIG. 3B illustrates a perspective view of the exemplary embodiment ofapplication FIG. 3A, with partial transparent view to illustratemultiple components formed by multilayer construction therein;

FIG. 3C illustrates a schematic view of the exemplary embodiment ofapplication FIG. 3A;

FIG. 4A illustrates a perspective view of yet another exemplaryembodiment of presently disclosed subject matter, with partialtransparent view to illustrate multiple components formed by multilayerconstruction therein;

FIG. 4B illustrates a top elevation view of selected layers within themultilayer construction of the exemplary embodiment of FIG. 4A;

FIG. 4C illustrates a schematic view of the exemplary embodiment ofapplication FIG. 4A;

FIG. 5A illustrates a perspective view of yet another exemplaryembodiment of presently disclosed subject matter, with partialtransparent view to illustrate multiple components formed by multilayerconstruction therein;

FIG. 5B illustrates a top elevation view of selected layers within themultilayer construction of the exemplary embodiment of FIG. 5A;

FIG. 6A illustrates an external perspective view of an exemplaryembodiment of a multiterminal multilayer device in accordance withpresently disclosed subject matter, for use in a stacked configurationwith a varistor device, all for use with added leads, as illustrated;

FIG. 6B illustrates a schematic view of the exemplary embodiment ofapplication FIG. 6A;

FIG. 6C illustrates an external perspective view of an exemplaryembodiment of a multiterminal multilayer device in accordance withpresently disclosed subject matter.

Repeat use of reference characters throughout the present specificationand appended drawings is intended to represent same or analogousfeatures, elements, or steps thereof.

DETAILED DESCRIPTION OF THE SUBJECT MATTER

Reference now will be made in detail to various embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations may be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment, may be used on another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Generally speaking, the present invention is directed to filter devices,such as integrated capacitor filters and in particular those withvaristor functionality. In general, a multiterminal multilayer ceramicdevice is provided. In one embodiment, the device may be provided with adiscrete varistor.

In general, a multilayer ceramic device, such as a multilayer ceramiccapacitor, can include a ceramic body with external electrodes. Theceramic body is fabricated by sintering a laminated body formed ofalternately stacked dielectric layers and internal electrodes. Each pairof neighboring internal electrodes faces each other with a dielectriclayer intervened therebetween and is electrically coupled to differentexternal electrodes, respectively.

In general, the dielectric layers can be made of any material generallyemployed in the art. For instance, the dielectric layer can be made of aceramic material including a titanate as a primary component. Thetitanate may include but is not limited to, barium titanate (BaTiO₃).The ceramic material may also contain an oxide of a rare-earth metaland/or a compound of such acceptor type element as Mn, V, Cr, Mo, Fe,Ni, Cu, Co, or the like. The titanate may also contain MgO, CaO, Mn₃O₄,Y₂O₃, V₂O₅, ZnO, ZrO₂, Nb₂O₅, Cr₂O₃, Fe₂O₃, P₂O₅, SrO, Na₂O, K₂O, Li₂O,SiO₂, WO₃ or the like. The ceramic material may also include otheradditives, organic solvents, plasticizers, binders, dispersing agents,or the like in addition to ceramic powder.

In general, the internal electrodes can be made of any materialgenerally employed in the art. For instance, the internal electrodes canbe formed by sintering a conductive paste whose main component is anoble metal material. These materials can include, but are not limitedto, palladium, palladium-silver alloy, nickel, and copper. For instance,in one embodiment, the electrodes may be made of nickel or a nickelalloy. The alloy may contain one or more of Mn, Cr, Co, Al, W and thelike, and an Ni content in the alloy is preferably 95% by weight ormore. The Ni or Ni alloy may contain 0.1% by weight or less of variousmicro-amount components such as P, C, Nb, Fe, Cl, B, Li, Na, K, F, S andthe like.

The ceramic body can be formed using any method generally known in theart. For instance, the ceramic body can be formed by forming a laminatedbody with alternately stacked ceramic sheets and patterned internalelectrodes, removing a binder off the laminated body, sintering thebinder removed laminated body in a non-oxidative atmosphere at a hightemperature ranging from 1200° C. to 1300° C., and re-oxidizing thesintered laminated body in the oxidative atmosphere.

In general, a varistor, can include a ceramic body with externalelectrodes. The ceramic body is fabricated by sintering a laminated bodyformed of alternately stacked ceramic layers and internal electrodes.Each pair of neighboring internal electrodes faces each other with aceramic layer intervened therebetween and is electrically coupled todifferent external electrodes, respectively.

In general, the ceramic layers can be made of any material generallyemployed in the art. For instance, the ceramic layers can be made from ametal oxide. In particular, the metal oxide may include zinc oxide andmay also include other oxides, such as those of bismuth, cobalt,antimony, manganese, chromium, boron, and/or tin.

In general, the internal electrodes can be made of any materialgenerally employed in the art. For instance, the internal electrodes canbe formed by sintering a conductive paste whose main component is anoble metal material. These materials can include, but are not limitedto, palladium, palladium-silver alloy, silver, nickel, and copper. Forinstance, in one embodiment, the electrodes may be made of nickel or anickel alloy. The alloy may contain one or more of Mn, Cr, Co, Al, W andthe like, and an Ni content in the alloy is preferably 95% by weight ormore. The Ni or Ni alloy may contain 0.1% by weight or less of variousmicro-amount components such as P, C, Nb, Fe, Cl, B, Li, Na, K, F, S andthe like.

Without intending to be limited by theory, a capacitor is an electricalcomponent that stores electrical energy in an electric field. Withoutintending to be limited by theory, a varistor is an electrical componentthat has an electrical resistance that can vary with the applied voltagethereby rendering it a voltage-dependent resistor. In combination, acapacitor and resistor can provide an RC circuit or filter.

In one embodiment, a multiterminal multilayer ceramic device is providedwith three or more capacitive elements. The three capacitors may involvetwo capacitors in series, which are in parallel with in turn a thirdelement. The device may also be provided in parallel with a discretevaristor. The multiterminal multilayer ceramic device may be a cofireddevice and/or the discrete varistor may be a discrete cofired varistor.

In one embodiment, the devices of the present disclosure may be packagedin overmolded three leaded components. In another embodiment, they mayalternatively be mounted as surface mount devices (SMD). With regards tothe former, it may provide an advantage in that it may simply assemblyby replacing three single discrete caps with a single integratedcapacitive device. With regards to the latter, it may provide anadvantage in that it may result in replacement of multiple discretecomponents on a printed circuit board (PCB), thereby saving space and insome instances lowering inductance.

Some presently disclosed exemplary embodiments result in integration ofcapacitive elements in a single cofired package. For yet otheralternatives, the addition of a varistor element provides transientprotection.

Additionally, other advantages may also exist. For instance, asubstantial reduction in device size can be obtained, which can resultin a reduction in the number of solder joints, which correspondinglyincreases reliability. Another facet is that the resulting integrateddevice can have much lower parasitic inductance than the correspondingnumber of discrete devices. Furthermore, lead wires allow an exemplarydevice to be installed within an electric motor housing. Also, suchdevice could also be made as SMD.

Another aspect of the present disclosure is that EMI and EMI/ESD circuitprotection can be obtained, which may be especially useful forparticular applications, such as for automotive applications. Thepresently disclosed subject matter may also be useful for motorstart-stop applications.

One embodiment of the present disclosure relates to a multiterminalmultilayer ceramic device, such as a multiterminal cofired multilayerceramic device, with multiple capacitive elements. The device comprisesa body, such as a six-sided generally rectangular body, havingcooperating multiple layers including electrode layers which in turnform integrated capacitive structures; a first region of such electrodelayers forming a split feedthrough type construction of two respectivecapacitors; a second region of such electrode layers forming an overlaptype construction of a multilayer ceramic capacitor; a first pair ofterminations external to such body and having opposite polarity; and asecond pair of terminations external to such body and having the samepolarity. Further, preferably such first pair of terminations is inseries connection with such second region capacitor, and such first pairof terminations and at least one of such second pair of terminations arein respective parallel connections with such two respective capacitorsof such first region, so that multiple capacitive elements areintegrated in a single package device, such as a single package cofireddevice.

In one embodiment, such first region of such electrode layers maycomprise at least a pair of layers, such as generally rectangularlayers, situated opposite a generally cross-shaped layer havingrespective front and back extending edges in respective contact withsuch second pair of terminations, and having side extending edges inrespective contact with such first pair of terminations.

In another embodiment, such second region of such electrode layers maycomprise at least paired alternating layers in an overlappedconfiguration with respective extending portions thereof in contact withrespective of such first pair of terminations.

In one embodiment, such two respective capacitors of such first regionmay be in series with each other, and both in parallel with suchmultilayer ceramic capacitor of such second region.

In another embodiment, such first and second pairs of terminations maybe situated on respective opposing-side pairs of sides of such body, andrespectively wrap-around therefrom to a designated bottom side of suchbody, for forming a surface mount device (SMD) configuration for suchdevice.

In accordance with one embodiment, first and second leads may berespectively attached to such first pair of terminations, and a thirdlead may be attached to at least one of such second pair ofterminations.

In accordance with another embodiment, such a multiterminal multilayerceramic device may further comprise a third region of such electrodelayers forming a split feedthrough type construction of an additionaltwo respective capacitors. Per such alternative, such first pair ofterminations and at least one of such second pair of terminations may bein respective parallel connections with such additional two respectivecapacitors of such third region.

In yet another embodiment, such second region of such electrode layersmay be between such first and third regions of such electrode layers.Per other variations, such body may have a pair of relatively elongatedsides and a pair of relatively shorter sides; such first pair ofterminations may reside respectively on such pair of relativelyelongated sides; and such second pair of terminations may residerespectively on such pair of relatively shorter sides.

For some embodiments, such pair of layers, such as generally rectangularlayers, of such first layer may have respectively different overlapareas with such generally cross-shaped layer of such first layer so thatdifferent capacitance values may result for such respective capacitorsof such first region. For others, such an exemplary multiterminalmultilayer ceramic device may further comprise a third region of suchelectrode layers forming a split feedthrough type construction of anadditional two respective capacitors, such third region comprising atleast a pair of layers, such as generally rectangular layers, havingrespective front and back extending edges in respective contact withsuch second pair of terminations, and having side extending edges inrespective contact with such first pair of terminations. In someembodiments, such pair of layers, such as generally rectangular layers,of such third layer may have respectively different overlap areas withsuch generally cross-shaped layer of such third layer so that differentcapacitance values result for such respective additional capacitors ofsuch third region.

In one embodiment, such electrode layers of such second region mayinclude relatively enlarged areas for forming a relatively increasedcapacitance value overlap type multilayer ceramic capacitor.

In one embodiment, a discrete varistor with a pair of externalterminations may be stacked relative to such device, with such first andsecond leads respectively attached to such pair of external terminationsof such varistor so that such device and such discrete varistor areconnected in parallel.

Another exemplary embodiment in accordance with presently disclosedsubject matter preferably relates to an integrated capacitor filter withvaristor functionality, comprising a discrete multiterminal multilayerceramic capacitor device, such as a cofired multilayer ceramic capacitordevice, with multiple capacitive elements, comprising a body, such as asix-sided generally rectangular, having cooperating multiple layersincluding electrode layers which in turn form integrated capacitivestructures; a first pair of capacitor device terminations external tosuch body and having opposite polarity; a second pair of capacitordevice terminations external to such body and having the same polarity;a first region of such electrode layers forming two respectivecapacitors; and a second region of such electrode layers forming amultilayer ceramic capacitor received in series connection between suchfirst pair of terminations. Such discrete multiterminal multilayerceramic capacitor device is preferably further combined with a discretevaristor, such as a discrete cofired varistor, comprising a body, suchas a six-sided generally rectangular, having a pair of varistorterminations external to such varistor body and having oppositepolarity; first and second leads respectively attached to such firstpair of capacitor device terminations and such pair of varistorterminations; and a third lead attached to at least one of such secondpair of capacitor device terminations.

In one embodiment, such first pair of capacitor device terminations andat least one of such second pair of capacitor device terminations may bein respective parallel connections with such two respective capacitorsof such first region. In another embodiment, such first region of suchelectrode layers may form a split feedthrough type construction of suchtwo respective capacitors; and such second region of such electrodelayers may form an overlap type construction of such multilayer ceramiccapacitor.

In accordance with another embodiment, a method is provided, includingfor example, for production of such devices. For example, one exemplaryembodiment of presently disclosed subject matter relates to a method forproviding a multiterminal multilayer ceramic device, such as a cofiredmultilayer ceramic device, with multiple capacitive elements. Suchmethod comprises providing a body, such as a six-sided generallyrectangular, having cooperating multiple layers including electrodelayers which are used to form integrated capacitive structures; forminga split feedthrough type construction of two respective capacitors in adesignated first region of such electrode layers; forming an overlaptype construction of a multilayer ceramic capacitor in a designatedsecond region of such electrode layers; applying a first pair ofterminations external to a pair of respective opposing sides of suchbody, and with such second region capacitor connected in series betweensuch first pair of terminations; and applying a second pair ofterminations external to at least portions of another pair of respectiveopposing sides of such body and having the same polarity, and with atleast one of such second pair of terminations and such first pair ofterminations in respective parallel connections with such two respectivecapacitors of such first region, so that multiple capacitive elementsare integrated in a single package device, such as a single packagecofired device.

In one embodiment, such first region of such electrode layers maycomprise at least a pair of layers, such as generally rectangularlayers, situated opposite a generally cross-shaped layer havingrespective front and back extending edges in respective contact withsuch second pair of terminations, and having side extending edges inrespective contact with such first pair of terminations; and such secondregion of such electrode layers may comprise at least paired alternatinglayers in an overlapped configuration with respective extending portionsthereof in contact with respective of such first pair of terminations.

For one embodiment, wherein such first and second pairs of terminationsmay respectively wrap-around to a designated bottom side of such body,for forming a surface mount device (SMD) configuration for such device.

For one embodiment, the method may further comprise forming anothersplit feedthrough type construction of two respective capacitors in adesignated third region of such electrode layers, with such tworespective capacitors of such third region connected respectively inparallel relative to at least one of such second pair of terminationsand such first pair of terminations.

In one embodiment, the method may comprise providing such pair oflayers, such as generally rectangular layers, of such first layer withrespectively different overlap areas with such generally cross-shapedlayer of such first layer so that different capacitance values resultfor such respective capacitors of such first region.

The method may also further comprise forming a split feedthrough typeconstruction of an additional two respective capacitors in a designatedthird region of such electrode layers, such third region comprising atleast a pair of layers, such as generally rectangular layers, havingrespective front and back extending edges in respective contact withsuch second pair of terminations, and having side extending edges inrespective contact with such first pair of terminations.

In one embodiment, the method may further include attaching first andsecond leads respectively to such first pair of terminations, andattaching a third lead to at least one of such second pair ofterminations. In one embodiment, the method may yet further includestacking relative to such device a discrete varistor with a pair ofexternal terminations, with such first and second leads respectivelyattached to such pair of external terminations of such varistor so thatsuch device and such discrete varistor are connected in parallel.

FIG. 1A illustrates an external perspective view of an exemplaryembodiment of a multiterminal multilayer device generally 100 inaccordance with presently disclosed subject matter. As illustrated, theexemplary embodiment 100 generally has a body, such as a six-sided body,generally 102, with external terminations 104, 106, 108, and 110. Allsuch external terminations present on a designated bottom side generally112 of device 100, for use such as in a surface mount device (SMD)configuration.

Device 100 in the exemplary embodiment illustrated may comprise amultiterminal multilayer ceramic device which is provided with three ormore capacitive elements. In some such embodiments, such threecapacitors may involve two capacitors in series, which are in parallelwith a third element. As understood by those of ordinary skill in theart relative to all embodiments described herein, cooperating layers inthe subject multilayer constructions comprise electrode layers which inturn form integrated capacitive structures.

FIG. 1B illustrates a perspective view of the exemplary embodimentgenerally 100 of application FIG. 1A, with partial transparent view toillustrate multiple components formed by multilayer constructiontherein. More specifically, as shown in such FIG. 1B, an upper or firstregion generally 114 of device 100 internally provides a splitfeedthrough type construction resulting in two respective exemplarycapacitors, while a lower or second region generally 116 of device 100internally provides more of a standard overlap multilayer capacitorconstruction. Thus, the representative exemplary embodiment of presentFIGS. 1A and 1B result in integration of capacitive elements in a singlepackage, such as a single cofired package.

More specifically, regarding upper region 114, a pair of layers 118 and120, such as generally rectangular layers 118 and 120, is juxtaposedopposite a representative cross-shaped layer 122. As represented, frontand back extending edges 124 and 126 of layer 122 are in respectivecontact with central (or second pair of) external terminations 108 and110, while side extending edges 128 and 130 are in respective contactwith side/end (or first pair of) terminations 104 and 106.

Regarding lower region 116, paired alternating layers 132/134 and136/138 are in standard overlapped configuration for formation of amultilayer capacitor within such region 116 of device 100. Also asshown, respective ends thereof 140 and 142 are in contact with externalend termination 104, while respective ends thereof 144 and 146 are incontact with external end termination 106.

FIG. 1C illustrates a perspective view of the exemplary embodiment 100of application FIG. 1A, with added lead configuration. Morespecifically, leads 148, 150, and 152 are respectively attached toexternal terminations 104, 108, and 106. Leads 148 and 152 mayconstitute first and second leads respectively attached to the firstpair of terminations 104 and 106, while lead 150 may constitute a thirdlead attached to at least one of the second pair of terminations 108 and110. Those of ordinary skill in the art will also understand thatterminations 108 and 110 are both connected to layer 122 of upper region114 of device 100, such that lead 150 may be connected with either suchtermination 108 or 110 with the same electrical circuitry consequences.The resulting configuration of application FIG. 1C is an overmoldedthree leaded component.

FIG. 1D illustrates a schematic view of the exemplary embodimentgenerally 100 of application FIG. 1A, in the connection/mountingconfiguration thereof as shown by application FIG. 1C. Morespecifically, leads 148, 150, and 152 are shown in respective contactwith series and parallel capacitors. The indicated capacitance valuesare intended as exemplary only, rather than limiting.

As illustrated, device 100 provides a single device solution forcontaining series and parallel capacitors. Upper region generally 114 ofdevice 100 shows two representative 10 nF capacitors 154 and 156 formedby the split feedthrough configuration of representative layers 118,122, and 130. Lower region generally 116 of device 100 shows a singlerepresentative 1 μF capacitor 158, such as would be formed from standardmultilayer capacitor constructions.

While various sizes may be practiced for any of the exemplaryembodiments disclosed herewith, device 100 may be regarded as beingrepresentative of a standard MLC case size, for example, a 1206 casesize. Of course, various sizes may be practiced in various embodiments,as needed or desired for a particular application. All such variationsand variations of exemplary capacitance values are intended to come withthe spirit and scope of the presently disclosed subject matter.Otherwise, device 100 in accordance with the presently disclosed subjectmatter represents an integrated three-terminal device with a standardmultilayer capacitor (MLC) in a designated lower region thereof combinedwith a split feedthrough in a designated upper region thereof. From amethod perspective, device 100 (integrated multiple capacitive elementsin a single package) in accordance with its description and uses herein,simplifies assembly of a leaded or SMD component by replacing threesingle discrete capacitors with a single integrated capacitive device.Particularly when used in an SMD configuration, multiple discretecomponents are avoided on a PCB, which saves space on the PCB whilelowering inductance.

FIG. 2 illustrates a perspective view of another exemplary embodimentgenerally 200 of presently disclosed subject matter. FIG. 2 provides apartially transparent view, similar to application FIG. 1B, toillustrate multiple components formed by multilayer constructiontherein. More specifically, device 200 has a pair of series capacitorssituated in a generally upper region 214 as well as a similar pair ofseries capacitors situated in a generally lower region 214′, withregions 214 and 214′ on either side of a central region generally 216 inwhich a single capacitor in parallel is formed. Accordingly, those ofordinary skill in the art will appreciate from the complete disclosureherewith that the internally configured embodiment of device 200 ofapplication FIG. 2 may nonetheless be also used with a standard packagesize (or other) and external termination configuration as represented byapplication FIG. 1A.

More specifically, as shown in such FIG. 2, upper and lower (first andthird) regions generally 214 and 214′ of device 200 internally providerespective split feedthrough type constructions resulting in two pairsof respective exemplary capacitors, while central or middle (second)region generally 216 of device 200 between regions 214 and 214′internally provides more of a standard overlap multilayer capacitorconstruction. Thus, the representative exemplary embodiment of presentFIG. 2 results in another exemplary embodiment of presently disclosedintegration of capacitive elements in a single package, such as a singlecofired package.

More specifically, regarding upper region 214, a pair of layers 218 and220, such as generally rectangular co-planar layers 218 and 220, isjuxtaposed opposite a representative cross-shaped layer 222. Asrepresented, front and back extending edges 224 and 226 of layer 222would be in respective contact with central external terminations 108and 110 (of application FIG. 1A), while side extending edges 228 and 230are in respective contact with side/end terminations 104 and 106 (ofapplication FIG. 1A). Similarly, regarding lower region 214′, a pair oflayers 218′ and 220′, such as generally rectangular layers 218′ and220′, are juxtaposed opposite a representative cross-shaped layer 222′.As represented, front and back extending edges 224′ and 226′ of layer222′ would be in respective contact with central external terminations108 and 110 (of application FIG. 1A), while side extending edges 228′and 230′ are in respective contact with side/end terminations 104 and106 (of application FIG. 1A).

Regarding middle or central region 216, paired alternating layers232/234 and 236/238 are in standard overlapped configuration forformation of a multilayer capacitor within such region 216 of device200. Also as shown, respective ends thereof 240 and 242 are in contactwith external end termination 104 (of application FIG. 1A), whilerespective ends thereof 244 and 246 are in contact with external endtermination 106 (of application FIG. 1A).

Similar to the potential alternative mounting of application embodiment100 of FIG. 1A in a leaded configuration of application FIG. 1C, device200 of application FIG. 2 may be mounted as a surface mount device, orassociated with leads in the configuration of application FIG. 1C.

FIG. 3A illustrates an external perspective view of another exemplaryembodiment 300 of a multiterminal multilayer device in accordance withpresently disclosed subject matter. FIG. 3B illustrates a perspectiveview of such exemplary embodiment 300 of application FIG. 3A, withpartial transparent view to illustrate multiple components formed bymultilayer construction therein, while FIG. 3C illustrates a schematicview of the exemplary embodiment 300 of application FIG. 3A.

More particularly, the alternative embodiment device 300 of presentlydisclosed subject matter may be regarded as a so-called reversearrangement configuration, which results in relatively lower inductance,as understood by those of ordinary skill in the art. In comparison withthe exemplary embodiment 100 of application FIGS. 1A and 1B, theelongated sides of exemplary body 302, such as the six-sided body 302,are terminated by external terminations 304 and 306, while the strippedexternal terminations 308 and 310 are formed on respective short sideends of body 302. Similar to application FIG. 1B, device 300 hasmultiple components formed by multiple layers in respective lower andupper regions 314 and 316, respectively, thereof. However, such layersare relatively rotated 90 degrees in comparison with the internalmultilayer structures of device 100, with reference to the relativelyelongated and relatively shortened sides thereof.

Further, the partial transparent view of FIG. 3A illustrates multiplecomponents formed by multilayer construction therein, including upperregion generally 314 of device 300 which internally provides a splitfeedthrough type construction resulting in two respective exemplarycapacitors, and including a lower region generally 316 of device 300which internally provides more of a standard overlap multilayercapacitor construction. Thus, the representative alternative exemplaryembodiment of present FIGS. 3A and 3B result again in integration ofcapacitive elements in a single package, such as a single cofiredpackage.

Regarding upper region 314, a pair of complementary co-planar layers 318and 320 (which may be generally T-shaped or otherwise shaped) arejuxtaposed opposite a representative cross-shaped layer 322. Asrepresented, side extending edges 324 and 326 of layer 322 are inrespective contact with stripped/side external terminations 308 and 310,while front and back extending edges 328 and 330 of members 318 and 320,respectively, are in respective contact with elongated side terminations304 and 306.

Regarding lower region 316, representative alternating layers 332 and336 are in standard overlapped configuration for formation of amultilayer capacitor within such region 316 of device 300. Also asshown, respective ends thereof 340 and 342 are in contact with externalelongated side terminations 304 and 306, respectively.

It is to be understood by those of ordinary skill in the art from thecomplete disclosure herewith that while device 300 is illustrated in anSMD configuration in FIG. 3A, such device 300 may be equally practicedin a leaded configuration, as represented by the exemplary embodiment ofFIG. 1C.

Similar to FIG. 1D, FIG. 3C illustrates a schematic view of theexemplary embodiment generally 300 of application FIG. 3A, in theconnection configuration thereof as shown by application FIG. 3A. Morespecifically, connections are listed as respective terminations 304,308, and 306, for circuitry connections as shown in respective contactwith series and parallel capacitors. The indicated capacitance valuesare intended as exemplary only, rather than limiting.

As illustrated, device 300 provides a single device solution forcontaining series and parallel capacitors. Upper region generally 314 ofdevice 300 shows two representative 10 nF capacitors 354 and 356 formedby the split feedthrough configuration of representative layers 318,322, and 330. Lower region generally 316 of device 300 shows a singlerepresentative 1 μF capacitor 358, such as would be formed from standardmultilayer capacitor constructions.

FIG. 4A illustrates a perspective view of yet another exemplaryembodiment generally 400 of presently disclosed subject matter, withpartial transparent view to illustrate multiple components formed bymultilayer construction therein. In particular, such exemplaryembodiment 400 makes use of different overlap areas (relative toexemplary embodiment 200) in order to provide different resultingcapacitances in an integrated device, such as an integrated cofireddevice.

More specifically, device 400 has a pair of series capacitors situatedin a generally upper region 414 as well as a similar pair of seriescapacitors situated in a generally lower region 414′, with regions 414and 414′ on either side of a central region generally 416 in which asingle capacitor in parallel is formed. Accordingly, those of ordinaryskill in the art will appreciate from the complete disclosure herewiththat the internally configured embodiment of device 400 of applicationFIG. 4A may nonetheless be also used with a standard package size (orother) and external termination configuration as represented byapplication FIG. 1A.

More specifically, as shown in such FIG. 4, upper and lower regionsgenerally 414 and 414′ of device 400 internally provide respective splitfeedthrough type constructions resulting in two pairs of respectiveexemplary capacitors, while central or middle region generally 416 ofdevice 400 between regions 414 and 414′ internally provides more of astandard overlap multilayer capacitor construction. Thus, therepresentative exemplary embodiment of present FIG. 4 results in anotherexemplary embodiment of presently disclosed integration of capacitiveelements in a single package, such as a single cofired package.

More specifically, regarding upper region 414, a pair of layers 418 and420, such as generally rectangular co-planar layers 418 and 420, isjuxtaposed opposite a representative cross-shaped layer 422. Asrepresented, front and back extending edges 424 and 426 of layer 422would be in respective contact with central external terminations 108and 110 (of application FIG. 1A), while side extending edges 428 and 430are in respective contact with side/end terminations 104 and 106 (ofapplication FIG. 1A). Similarly, regarding lower region 414′, a pair oflayers 418′ and 420′, such as generally rectangular layers 418′ and420′, are juxtaposed opposite a representative cross-shaped layer 422′.As represented, front and back extending edges 424′ and 426′ of layer422′ would be in respective contact with central external terminations108 and 110 (of application FIG. 1A), while side extending edges 428′and 430′ are in respective contact with side/end terminations 104 and106 (of application FIG. 1A).

Regarding middle or central region 416, paired alternating layers432/434 and 436/438 are in standard overlapped configuration forformation of a multilayer capacitor within such region 416 of device400. Also as shown, respective ends thereof 440 and 442 are in contactwith external end termination 104 (of application FIG. 1A), whilerespective ends thereof 444 and 446 are in contact with external endtermination 106 (of application FIG. 1A).

Similar to the potential alternative mounting of application embodiment100 of FIG. 1A in a leaded configuration of application FIG. 1C, device400 of application FIG. 4A may be mounted as a surface mount device, orassociated with leads in the configuration of application FIG. 1C.

FIG. 4B illustrates a top elevation view of selected layers within theupper region 414 generally of the multilayer construction of theexemplary embodiment 400 of FIG. 4A. More specifically, representativelayers 418, 420, and 422 are shown. As understood by those of ordinaryskill in the art, the amount of surface area overlapped between opposinglayers contributes to determining the value of resulting capacitanceformed thereby. In this instance, the respective layers 418, 420, and422 are configured as shown such that a greater overlap area 423 resideson one side of region 414 than for the overlap area 425 residing on theother side of region 414. As is understood, such different overlap areahelp form different capacitances, as otherwise reflected herein.Specifically, FIG. 4C illustrates a schematic view of the exemplaryembodiment 400 of application FIGS. 4A and 4B. As shown, the two seriescapacitances formed are of unequal value, as a reflection of the unevendegrees of respective overlap for areas 423 and 425. While variationsmay be practiced, the exemplary embodiment 400 illustrated results inexample capacitances for capacitors 454 and 456 of 20 nF and 10 nF,respectively, and 1 μF for capacitor 458. While a leaded configurationmay be practiced, terminations 404, 408, and 406 are represented in theschematic view of FIG. 3C, to reflect a surface mount deviceconfiguration of embodiment 400.

FIG. 5A illustrates a perspective view of yet another exemplaryembodiment 500 of presently disclosed subject matter, with partialtransparent view to illustrate multiple components formed by multilayerconstruction therein. In particular, relatively enlarged electrodes(such as T-shaped designs) may be used to increase the relative degreeof overlap, to thereby correspondingly increase capacitance values. Theymay also be used to provide other beneficial characteristics including,but not limited to, reducing the inductance and/or the equivalent seriesresistance (ESR).

More specifically, as shown in such FIG. 5A, an upper region generally514 of device 500 internally provides a split feedthrough typeconstruction resulting in two respective exemplary capacitors, while alower region generally 516 of device 500 internally provides an overlapmultilayer capacitor construction. Thus, the representative exemplaryembodiment of present FIG. 5A results in integration of capacitiveelements in a single package, such as a single cofired package.

More specifically, regarding upper region 514, a pair of layers 518 and520, such as generally rectangular layers 518 and 520, is juxtaposedopposite a representative cross-shaped layer 522. As represented, frontand back extending edges 524 and 526 of layer 522 are in respectivecontact with central external terminations 108 and 110 (application FIG.1A for SMD configuration), while side extending edges 528 and 530 are inrespective contact with side/end terminations 104 and 106 (applicationFIG. 1A).

Regarding lower region 516, paired alternating layers 532/534 and536/538 are in standard overlapped configuration for formation of amultilayer capacitor within such region 516 of device 500. Also asshown, respective ends thereof 540 and 542 are in contact with externalend termination 104 (application FIG. 1A), while respective ends thereof544 and 546 are in contact with external end termination 106(application FIG. 1A).

FIG. 5B illustrates a top elevation view of selected layers 532 and 536within the lower region 516 of multilayer construction of the exemplaryembodiment 500 of FIG. 5A. While various shapes may be practiced, asshown such capacitor electrode layers 532 and 536 may in some instancescomprise T-shaped layers. As understood by those of ordinary skill inthe art, overlap region or area 533 contributes to forming the resultingcapacitance, such that relatively enlarging such overlap area relativelyincreases corresponding capacitance values (if all other factors areconstant). They may also be used to provide other beneficialcharacteristics including, but not limited to, reducing the inductanceand/or the equivalent series resistance (ESR).

As otherwise disclosed herewith, the addition of exemplary embodimentsherewith in parallel with a discrete varistor, such as a discretecofired varistor, element helps to provide transient protection to theresulting combination. More specifically, FIG. 6A illustrates anexternal perspective view of an exemplary embodiment of a multiterminalmultilayer device generally 600 in accordance with presently disclosedsubject matter, for use in a stacked configuration with a varistordevice generally 660, all for use with respective added leads 648, 650,and 652, as illustrated. As discussed further herein, FIG. 6Billustrates a schematic view of the exemplary embodiment 600 ofapplication FIG. 6A.

FIG. 6A illustrates an external perspective view of an exemplaryembodiment of a multiterminal multilayer device generally 600 inaccordance with presently disclosed subject matter. As illustrated, theexemplary embodiment 600 generally has body, such as a six-sided body,generally 602, with external terminations 604, 606, 608, and 610. Device600 in the exemplary embodiment illustrated may comprise a multiterminalmultilayer ceramic device, such as a cofired multilayer ceramic device,which is provided with three or more capacitive elements. In some suchembodiments, such three capacitors may involve two capacitors in series,which are in parallel with a third element.

FIG. 6A also illustrates a perspective view of the exemplary embodiment600, with added varistor device generally 660. Such device 660 may alsohave a standard 1206 case size, or other standard or non-standard casesize. As shown, varistor 660 also has external terminations generally662 and 664. Further per FIG. 6A, a lead configuration arrangement maybe used to place device 600 and varistor 660 in parallel relative toeach other. More specifically, leads 648, 650, and 652 are respectivelyattached to external (capacitor device) terminations 604, 608, and 606of device 600, while leads 648 and 652 and respectively connected asshown to external side (varistor) terminations 662 and 664 of varistor660. The resulting configuration of application FIG. 6A is an overmoldedthree leaded component.

FIG. 6B illustrates a schematic view of the exemplary embodimentgenerally 600 of application FIG. 6A, in the connection/mountingconfiguration thereof as shown by application FIG. 6A. Morespecifically, leads 648, 650, and 652 are shown in respective contactwith series and parallel capacitors. The indicated capacitance valuesare intended as exemplary only, rather than limiting. Varistor 660 islikewise in contact with leads 648 and 652 as illustrated, so as to bein parallel relationship with device 600. The indicated varistorcharacteristics are intended as exemplary only, rather than limiting.

FIG. 6C illustrates a perspective view of a multiterminal multilayerdevice. In general, FIG. 6C illustrates the device of FIG. 6A in anotherperspective. For instance, the embodiment of FIG. 6C provides device600, such as a multilayer ceramic device, on bottom with varistor 660 ontop. Such a configuration can allow for use as a surface mount deviceafter combining, such as via soldering, device 600 and varistor 660together. Additionally, the embodiment as illustrated in FIG. 6C isprovided without the leads illustrated in FIG. 6A. However, it should beunderstood that leads may also be employed when in such a configuration.

As illustrated, device 600 provides a single device solution forcontaining series and parallel capacitors. Device 600 shows tworepresentative 10 nF capacitors 654 and 656, such as may be formed by asplit feedthrough configuration of multiple layers in an isolated regionof device 600. Device 600 also provides as shown a single representative1 μF capacitor 658, such as may be formed from standard multilayercapacitor constructions in another region of device 600.

While various sizes may be practiced for any of the exemplaryembodiments disclosed herewith, device 600 and varistor 660 may beregarded as being representative of a standard MLC case size, forexample, a 1206 case size. Of course, various sizes may be practiced invarious embodiments, as needed or desired for a particular application.All such variations and variations of exemplary capacitance values areintended to come with the spirit and scope of the presently disclosedsubject matter.

As shown by the disclosure herewith, for some embodiments where used inan SMD arrangement, the presently disclosed subject matter may result inreplacement of multiple discrete components on a printed circuit board(PCB), thereby saving space and in some instances lowering inductance.All of such presently disclosed exemplary embodiments may in some usesthereof by packaged in overmolded three leaded components. Per presentlydisclosed subject matter, a substantial reduction in device size isobtained, which results in reduction in the number of solder joints,which correspondingly increases reliability.

Also, individual steps in achieving the disclosed configurations areonly intended as representative thereof, and do not denote required useof other aspects beyond the general nature of the disclosure otherwiseindicated. For example, those of ordinary skill in the art willrecognize that selected steps may be practiced to produce a particulardesign selected for a given application of the presently disclosedsubject matter.

While such presently disclosed subject matter has been described indetail with respect to specific embodiments thereof, it will beappreciated that those skilled in the art, upon attaining anunderstanding of the foregoing may readily produce alterations to,variations of, and equivalents to such embodiments. Accordingly, thescope of the present disclosure is by way of example rather than by wayof limitation, and the subject disclosure does not preclude inclusion ofsuch modifications, variations and/or additions to the presentlydisclosed subject matter as would be readily apparent to one of ordinaryskill in the art.

What is claimed is:
 1. A multiterminal multilayer ceramic device withmultiple capacitive elements, comprising: a body having cooperatingmultiple layers including electrode layers to form integrated capacitivestructures; a first region of said electrode layers forming a splitfeedthrough type construction of two respective capacitors; a secondregion of said electrode layers forming an overlap type construction ofa multilayer ceramic capacitor; a first pair of terminations external tosaid body and having opposite polarity; and a second pair ofterminations external to said body and having the same polarity; whereinsaid first pair of terminations is in series connection with said secondregion capacitor, and said first pair of terminations and at least oneof said second pair of terminations are in respective parallelconnections with said two respective capacitors of said first region, sothat multiple capacitive elements are integrated in a single packagedevice.
 2. A multiterminal multilayer ceramic device as in claim 1,wherein said first region of said electrode layers comprises at least apair of layers situated opposite a generally cross-shaped layer havingrespective front and back extending edges in respective contact withsaid second pair of terminations, and having side extending edges inrespective contact with said first pair of terminations.
 3. Amultiterminal multilayer ceramic device as in claim 1, wherein saidsecond region of said electrode layers comprises at least pairedalternating layers in an overlapped configuration with respectiveextending portions thereof in contact with respective of said first pairof terminations.
 4. A multiterminal multilayer ceramic device as inclaim 1, wherein said two respective capacitors of said first region arein series with each other, and both in parallel with said multilayerceramic capacitor of said second region.
 5. A multiterminal multilayerceramic device as in claim 1, wherein said first and second pairs ofterminations are situated on respective opposing-side pairs of sides ofsaid body, and respectively wrap-around therefrom to a designated bottomside of said body, for forming a surface mount device (SMD)configuration for said device.
 6. A multiterminal multilayer ceramicdevice as in claim 1, further including first and second leadsrespectively attached to said first pair of terminations, and a thirdlead attached to at least one of said second pair of terminations.
 7. Amultiterminal multilayer ceramic device as in claim 1, furthercomprising: a third region of said electrode layers forming a splitfeedthrough type construction of an additional two respectivecapacitors; wherein said first pair of terminations and at least one ofsaid second pair of terminations are in respective parallel connectionswith said additional two respective capacitors of said third region. 8.A multiterminal multilayer ceramic device as in claim 1, wherein saidsecond region of said electrode layers is between said first and thirdregions of said electrode layers.
 9. A multiterminal multilayer ceramicdevice as in claim 1, wherein: said body has a pair of relativelyelongated sides and a pair of relatively shorter sides; said first pairof terminations reside respectively on said pair of relatively elongatedsides; and said second pair of terminations resides respectively on saidpair of relatively shorter sides.
 10. A multiterminal multilayer ceramicdevice as in claim 2, wherein said pair of layers of said first layerhave respectively different overlap areas with said generallycross-shaped layer of said first layer so that different capacitancevalues result for said respective capacitors of said first region.
 11. Amultiterminal multilayer ceramic device as in claim 10, furthercomprising: a third region of said electrode layers forming a splitfeedthrough type construction of an additional two respectivecapacitors, said third region comprising at least a pair of layershaving respective front and back extending edges in respective contactwith said second pair of terminations, and having side extending edgesin respective contact with said first pair of terminations; wherein saidpair of layers of said third layer have respectively different overlapareas with said generally cross-shaped layer of said third layer so thatdifferent capacitance values result for said respective additionalcapacitors of said third region.
 12. A multiterminal multilayer ceramicdevice as in claim 1, wherein said electrode layers of said secondregion include relatively enlarged areas for forming a relativelyincreased capacitance value overlap type multilayer ceramic capacitor.13. A multiterminal multilayer ceramic device as in claim 6, wherein adiscrete varistor with a pair of external terminations is stackedrelative to said device, with said first and second leads respectivelyattached to said pair of external terminations of said varistor so thatsaid device and said discrete varistor are connected in parallel.
 14. Anintegrated capacitor filter with varistor functionality, comprising: adiscrete multiterminal multilayer ceramic capacitor device with multiplecapacitive elements, comprising a body having cooperating multiplelayers including electrode layers which in turn form integratedcapacitive structures; a first pair of capacitor device terminationsexternal to said body and having opposite polarity; a second pair ofcapacitor device terminations external to said body and having the samepolarity; a first region of said electrode layers forming two respectivecapacitors; and a second region of said electrode layers forming amultilayer ceramic capacitor received in series connection between saidfirst pair of terminations; a discrete varistor comprising a body havinga pair of varistor terminations external to said varistor body andhaving opposite polarity; first and second leads respectively attachedto said first pair of capacitor device terminations and said pair ofvaristor terminations; and a third lead attached to at least one of saidsecond pair of capacitor device terminations.
 15. An integratedcapacitor filter with varistor functionality as in claim 14, whereinsaid first pair of capacitor device terminations and at least one ofsaid second pair of capacitor device terminations are in respectiveparallel connections with said two respective capacitors of said firstregion.
 16. An integrated capacitor filter with varistor functionalityas in claim 14, wherein: said first region of said electrode layersforms a split feedthrough type construction of said two respectivecapacitors; and said second region of said electrode layers forms anoverlap type construction of said multilayer ceramic capacitor.
 17. Amethod for providing a multiterminal multilayer ceramic device withmultiple capacitive elements, comprising: providing a body havingcooperating multiple layers including electrode layers which are used toform integrated capacitive structures; forming a split feedthrough typeconstruction of two respective capacitors in a designated first regionof said electrode layers; forming an overlap type construction of amultilayer ceramic capacitor in a designated second region of saidelectrode layers; applying a first pair of terminations external to apair of respective opposing sides of said body, and with said secondregion capacitor connected in series between said first pair ofterminations; and applying a second pair of terminations external to atleast portions of another pair of respective opposing sides of said bodyand having the same polarity, and with at least one of said second pairof terminations and said first pair of terminations in respectiveparallel connections with said two respective capacitors of said firstregion, so that multiple capacitive elements are integrated in a singlepackage device.
 18. The method as in claim 17, wherein: said firstregion of said electrode layers comprises at least a pair of layerssituated opposite a generally cross-shaped layer having respective frontand back extending edges in respective contact with said second pair ofterminations, and having side extending edges in respective contact withsaid first pair of terminations; and said second region of saidelectrode layers comprises at least paired alternating layers in anoverlapped configuration with respective extending portions thereof incontact with respective of said first pair of terminations.
 19. Themethod as in claim 17, wherein said first and second pairs ofterminations respectively wrap-around to a designated bottom side ofsaid body, for forming a surface mount device (SMD) configuration forsaid device.
 20. The method as in claim 17, further comprising forminganother split feedthrough type construction of two respective capacitorsin a designated third region of said electrode layers, with said tworespective capacitors of said third region connected respectively inparallel relative to at least one of said second pair of terminationsand said first pair of terminations.
 21. The method as in claim 18,further including providing said pair of layers of said first layer withrespectively different overlap areas with said generally cross-shapedlayer of said first layer so that different capacitance values resultfor said respective capacitors of said first region.
 22. The method asin claim 17, further comprising forming a split feedthrough typeconstruction of an additional two respective capacitors in a designatedthird region of said electrode layers, said third region comprising atleast a pair of layers having respective front and back extending edgesin respective contact with said second pair of terminations, and havingside extending edges in respective contact with said first pair ofterminations.
 23. The method as in claim 17, further including attachingfirst and second leads respectively to said first pair of terminations,and attaching a third lead to at least one of said second pair ofterminations.
 24. The method as in claim 23, further including stackingrelative to said device a discrete varistor with a pair of externalterminations, with said first and second leads respectively attached tosaid pair of external terminations of said varistor so that said deviceand said discrete varistor are connected in parallel.